jarvis



Jan. 29, 1957 APPARATUS FOR EQUALIZING TENSION IN ELASTIC RIBBON P. L.JARVIS RN a / l A l 2 Sheets-Sheeil 1 ATTORNEYJS Jan. 29, 1957 P. JARvls2,779,552

APPARATUS FOR EQUALIZING TENSION IN ELASTIC RIBBON Filed July 19, 1955 2Sheets-Sheet 2 gg INVENTOR Plu'lij) .@arvis ATTORNEYS United StatesPatent O APPARATUS FOR EQUALIZING TENSION IN ELASTIC RIBBON Philip L.Jarvis, Pawtucket, R. I., assignor to Jarvis Mfg. Corp., Pawtucket, R.I., a corporation of Rhode Island Application July 19, 1955, Serial No.523,033

7 Claims. (Cl. 242-153) This invention is directed to a method andapparatus for applying a uniform tension to relatively narrow elasticribbon material.

With more specificness my invention is directed to apparatus throughwhich relatively narrow elastic ribbon stock is passed as it is led to abraiding machine, covering machine or a winding and reeling point suchthat a desired uniform tension is applied and the ribbon leaves theapparatus with a uniform tension.

One of the objects of my invention is to lead elastic ribbon stock overa plurality of equal diameter pulleys to even out the tension thereinand to reverse the direction of ribbon travel between pulleys, to passthe ribbon over an enlarged diameter pulley, thence reversing thedirection of travel of the ribbon and passing it over a plurality offriction surface pulleys having a diameter intermediate thefirst-mentioned pulleys and the enlarged diameter.

Another object of my invention is to provide a plurality ofinterconnected pulleys on a common axis wherein a first group of thepulleys to which an elastic ribbon is led have the smallest diameter,the intermediate pulley of said pulleys having the greatest diameter,and the last pulleys over which the ribbon is led having a diameter inbetween the smallest and the largest diameter pulleys along withreversing means positioned in spaced relation adjacent the pulleys andover which the ribbon is led to reverse its general direction as itpasses from one pulley to the next pulley and wherein brake means areprovided for limiting the rate of rotation of said pulleys over whichsaid ribbon is pulled.

A further object of my invention is to provide a tension apparatus asjust above described in which the pulleys have anti-friction surfacesover which the ribbon travels so that any relative movement, if any,between ribbon and that anti-friction surface is minimized.

A still further object of my invention is to provide a method of eveningout the tension in a relativelyfnarrow elastic ribbon by first applyinga slight tension thereon and subsequently relaxing the relatively greattension to a tension application intermediate the iirst applied an therelatively great applied tensions.

Still further objects and the entire scope of applicability of thepresent invention will become apparent from the detailed descriptiongiven hereinafter; it should be understood, however, that the detaileddescription and specific example given by way of illustration only and,while indicating preferred embodiment of the invention, is not given byway of limitation, since various changes and modifications within thespirit and Iscope of the invention will become apparent to those skilledinthe art from this detailed description.

For a more complete understanding of the nature and scope of myinvention, reference may be had to the drawings in which:

Fig. l is a perspective view of my tensioning apparatus showing the pathof travel of an elastic ribbon therethrough;

A 2,779,552 Patented Jan. 29, 1957,

Fig. 2 is a plan view of my tensioning apparatus; Fig. 3 is a frontelevation of the tensioning apparatus as viewed from the bottom of Fig.2; and

ice

Fig. 4 is a sectional view of the composite pulleys along line 4-4 ofFig. 2.

Throughout the description like reference characters refer to similarelements.

In Fig. l the tensioning apparatus is generally indicated at 10 and arelatively narrow elastic ribbon is led from a supply spool F supportedon a vertically extending spindle 11. The apparatus is built up about aframe generally indicated at 11 having an angle iro-n member 12positioned horizontally and with a portion of one web, the upper web, asindicated at 13, bent up at a right angle and provided with aperture 13to receive bolts or rivets and secure it to a post 15. The verticallyextending web 12 of the angle ir0nv12 is apertured at one end thereof toreceive a bolt 16 which is secured thereto by lock nuts 17 and 18, seeFig. 4.

Still continuing with the description of the frame 12, a dependingbracket 19 having an up-turned end 19 is attached to the lower edge ofvertical ange 12 opposite to the apertured end as by welding. At theopposite end from angle iron 12 from bracket 19 and the vertical flange12 is attached a right angle bracket 20 having an upturned end 20 whichis attached to the vertical liange 12 of angle iron 12 as by welding orthe whole frame may be cut out and bent up from a single piece of stock.Bracket 20 has its extreme outer end bent at right angles as at 20 andis apertured to receive a bolt 21 which serves as an axle mounting for apulley 22, to be described later.

Mounted on bolt 16 is an integrally formed plurality of pulleysgenerally indicated at 24 having the righthanded pulley 25 thereof, seeFig. 4, provided with groove 25 therein which receives a belt or strap26 that supports a weight 27, see Fig. l, so as to provide a frictionbrake or drag for the plurality of pulleys generally indicated at 24.Next adjacent to the left of pulley 25 are two of the smallest diameterpulleys 28 and 29 having equal diameters, such pulleys being the firstpulleys of the group of pulleys 24 to which the elastic ribbon R is ledin its passage through the uniform tensioning applying apparatus. Nextadjacent to the left of pulleys 28 and 29 is a middle r pulley 30 havinga diameter which is the greatest diameter of all of the pulleys and nextadjacent this pulley 30 are the last pulleys 31 and 32 having a diameterintermediate the diameter of the smallest pulleys 28 and 29 and thelargest pulley 30. Each of the pulleys 31 and 32 are provided withfriction surfacing 33, see Fig. 2, consisting of a strip of cork orother like material so as to provide for minimum slippage of the elasticribbon when passing thereover.

Associated with each o-f the pulleys is a reversing means for the ribbonconsisting of spaced apart upstanding posts 34-38, inclusive, aboutwhichthe ribbon R is led from off one pulley and onto the next pulleythere adjacent such that the general direction of the ribbon travel isreversed. These posts 34-38 extend upwardly from the bracket 19 and aregenerally perpendicular to a plane (not shown) containing the bracket 19and extending below the bolt 16 mounting the plurality ofintegrallyconnected pulleys 24.

Referring to Figs. 2 and 3, it will be noted that pulley 22 supported bybracket 20 is in alignment with the last pulley 32 over which the ribbontravels in its transit through the tension applying apparatus. Pulley 32is an idling pulley and is merely a guide pulley under which the ribbonR is led as shown in Fig. l as it leaves the apparatus and passes to thebraiding point, covering machine or winding and reeling point.

In the specific example here illustrated pulleys 28 and 29, theYsmallest pulleys, or the first pulleys, have a diameter of 2 inches,pulley 30 has a diameter of 2% inches. Considering the pulley 3l? havinga diameter represented by 100%, pulleys 28 and 29 have a diameter ofapproximately 72.7% of the largest pulley while the intermediate pulleys31 and 32 have a diameter of approximately 90.8% of pulley 30. The widthof the pulley surface in each of the pulleys is. here illustrated asbeing about 7/16, and these pulleys easily accommodate elastic ribbonshaving a very narrow width up to a larger width substantially' ti ewidth of the pulley surface. It will be noted in the transit of theribbon R over the pulleys and the reversing means, namely, the posts34-38, that the ribbon R passes adjacent the right of post 34 overpulley 28, see Fig. 2, over post 35v and then over pulley 29 andlikewise over post 36, pulley 30, post 37, pulley 31, post 38, and thelast pulley 32 to the underneath surface of pulley 23.

In carrying out this uniform tensioning of the ribbon R it will be notedthat the ribbon transits two small diarneter pulleys, and the tensiontherein is more or less relaxed. On leaving the post following the smallpulleys, namely, the post 36, the ribbon is passed over the largestdiameter pulley where it is stretched or placed under greater tensionand thence it is led over post 37 and to the intermediate diameterpulleys 31 and 32 whose. surfaces 33 have the friction whereby theribbon has little, if any, slippage when transiting these pulleys 31 and32 and thus on relaxing the tension from the stretching pulley 30 whilepassing over the last pulleys 31 and 32, the tension is evened out andthe ribbon leaves the pulley 32 with uniform tension. Just why thisphenomenon takes. place is not fully understood, but by this combinationof relationship of diameters of the plurality of pulleys over which theelastic ribbon is pulled in combinationV with the reversing means, suchas the posts 34-33, and the braking means on the pulleys, the ribbon isgiven a uniform tension.

While l have disclosed a brake means consisting of the drag belt 26 andthe weight 27 suspended therefrom to apply a drag on the pulley 25 andin turn the integrally connected other pulleys, this can be accomplishedby other means (not shown) such as a spring applying pressure to the endof the pulleys or by a mere tangential drag applied to the pulleys.

This apparatus and method of evening out the tension in elastic ribbonto render it more workable for braiding, covering or even reeling hasproved to be highly successful yet just what the explanation is as towhy it so successfully applies an even tension is not fully understood.Progressive steps of applying .tension to elastic ribbon are lknown inthe prior art but evening out on a rst set of pulleys, applying arelatively great tension and following the relaxing of the great tensionby an intermediate application of tension seems to accomplish thedesired result.

I claim as my invention:

l. Apparatus for applying a uniform tension to a relatively narrow bandof elastic ribbon material which comprises a support frame, a pluralityof parallel adjacent interconnected pulleys for rotation at the samespeed mounted on said frame on a common axis and over which said ribbonis led from a supply to a take off point andY means associated with saidframe and positioned in spaced relation to said pulleys and over whichsaid ribbon is led from off one pulley onto the one next adjacent toreverse the general direction of travel of the ribbon, the first two ofsaid pulleys to which the ribbon is applied to condition it withauniform tension therein being equal and having the smallest diameterofthe pulleys, the; pulleyl next adjacent to the second. Pulley having thegreatest diameter, and the last two pulleys having equal diametersintermediate the smallest and greatest diameters of the pulleys andprovided with friction surfaces over which said ribbon is led to therebyprovide a minimum of relative movement between ribbon and pulley surfaceand means for applying a braking drag to said plurality ofinterconnected pulleys.

2. Apparatus for applying a uniform tension to a relatively narrow bandof elastic ribbon material which comprises a support frame, a pluralityof parallel adjacent interconnected pulleys for rotation at the samespeed mounted on said frame on a common axis and over which said ribbonis led from a supply to a take oif point and means associated with saidframe and positioned in spaced relation to said pulleys and over whichsaid ribbon is led from off one pulley onto the one next adjacent toreverse the general direction of travel of the ribbon, the rst pulley towhich the ribbon is applied to condition it having the smallest diameterof the pulleys, the pulley next adjacent to the first pulley having thegreatest diameter and the last pulley having a diameter intermediate thediameters of the smallest and largest pulleys, and means for applying abraking drag to said plurality of interconnected pulleys.

3. Apparatus of the character described in claim 2 wherein said lastpulley has a friction surface thereon over which said ribbon is led tothereby provide a minimum of relative movement or slippage betweenribbon and the surface of that pulley.

4. Apparatus for applying a uniform tension to arela-5 tively narrowband of elastic ribbon material which comprises a support frame, aplurality of parallel adjacent interconnected pulleys for rotation atthe same speed mounted on said frame on a common axis and over whichsaid* ribbon isy led from a supplyA to a take off point and reversingmeans associated with said frame and positioned inl spaced relation tosaid pulleys and over which said ribbon is led from off one pulley ontothe one next adjacent to reverse the general direction of travel of theribbon, said intermediate pulley having the largest diameter, the firstpulleys to which the ribbon is led onto the apparatus having equaldiameters of about 72% of the diameter of theintermediate pulley and thelast pulleys over which the ribbon is led on leaving the apparatushaving a diameter of about of the diameter of said intermediate pulley,said last pulleys over which the ribbon is led on leaving the apparatushaving friction surfaces whereby a minimum of slippage occurs betweenthe ribbon and their surfaces and meansl for applying a braking drag tosaid plurality of interconnected pulleys.

5. Apparatus of the character described in claim 4 wherein said rstpulleys comprise two pulleys and said last pulleys comprise two pulleysand said reversing means for reversing the general direction ofy ribbontravel between pulleys comprises a xed post about which said ribbon isled.

6. Apparatusv of the character described in claim 5y wherein said brakemeans comprises a pulley affixed to said other pulleys and on the commonaxis therewith and having a strap led thereover and suspending a weighttherefrom to afford a braking drag to the rotation of said pulleys;

7. Apparatus of the character described in claim 6` includinga guideribbon pulley on said frame in line with the last pulley'over which saidribbon is led as it leaves said apparatus and positioned on the oppositeside of said plurality of pulleys from said reverse means.

References Cited in the file of this patent UNITED STATESv PATE-N TS

